His birth date is narrated to be on the 15th of Jamad-ul-Avval of year 35, 36 or 38, or 48 (there are different opinions on the exact day, and the confusion has raised because all Imam Hossein’s sons were called Ali) or 19th November 655 (656, or 658). His father was Imam Hossein AS, shiites’ third Imam and his mother was called Shahrbanu, some ascribing her to the daughter of the Persian king, Yazdgerd, but many opposing such claim.
Imam Sajjad PBUH, known as Zayn-ul-Abedin or the model of worshippers, was Imam Hossein’s only remaining son after the Battle of Ashura. Although, Imam Sajjad was an adolescent by the time (about 14 years old), but by God’s will and help, his sickness during the Battle of Ashura saved him from being murdered like the rest of his family. In the years that followed the Battle, Imam Sajjad did not stop retaliating his father’s martyrdom. However, Imam Sajjad’s retaliation was not an armed one, neither was it violent. Instead Imam Sajjad chose the book to spread out his message. His two famous books Sahifah Sajjadiyah and his Treatise on Human Rights are famous and translated into many languages. Although the Sahifah Sajjadiyah seems to be a book of prayers, but in fact, it is a living instruction and a companion to his Treatise of Human Rights.
He lived 35 years after Imam Hossein AS, and was martyred by one of the Ummayah’s caliphates, Valid-ibn-Abdolmalek.